The invention relates to a device for treating combustion gases from combustion units, comprising a vessel, a supply duct for the combustion gases, an exhaust duct for the treated combustion gases, washing liquid provided at two different filling levels in the lower part of the vessel, with the end of the supply duct being dipped into the washing liquid as long as the liquid is at its maximum filling level, and being spaced therefrom if the liquid is at its minimum filling level, and downwardly directed spray nozzles in the upper part of the vessel, with the washing liquid discharged through the nozzles crossing the flow path of the combustion gases.
A device of this kind separating primarily solid particles from smoke may be learned from German Pat. No. 51896, for example. Waste gases, particularly from industrial plants, are directed through or close over the washing liquid, or sprinkled with washing liquid from sprinkling heads, whereby the solid particles are separated from the gaseous ones. Depending on the nature of the liquid, which may be water or an organic solvent, gaseous components of the smoke also may dissolve. The smoke gases flow through the upper part of the vessel without being guided, so that the solvent effect on gaseous components by the washing liquid discharged from the sprinkling heads is not particularly strong. No shutoff mechanism is provided within the device which would prevent the smoke gases from passing therethrough.
To separate solid particles from a gas stream,, it is further known, from Austrian Pat. No. 285552, to direct the gas stream through a cylindrical tube through which the discharge duct extends coaxially. The annular space thus formed accommodates downwardly directed spray nozzles which are skirted by the gases flowing downwardly and an annular venturi nozzle is provided below the spray nozzles, effecting the separation of the solid matter. Here again, no flow lock is provided within the device.
Finally, Swiss Pat. No. 463679 discloses a flue gas washing plant comprising a vessel with a washing liquid, where the flow gases escape from a supply tube having its outlet end below the water surface, and are taken by suction through the washing unit by means of an exhauster mounted in the outlet duct. The passage of the flue gases is interrupted by switching off the exhauster.